Almost all designs used in practice are constructed as if there is only one objective in the study. Rising experimental costs have led researchers to use efficient designs that can more adequately meet their practical goals and concerns. In particular, designs should be able to capture the multiple goals embedded in most studies, the possibly unequal importance of these goals and other constraints, such as model uncertainty, a restricted design space and potentially missing trials. We will construct multiple-objective optimal designs that incorporate these and other practical constraints. We also work with environmental health scientists and apply optimal design ideas to design a study for estimating the threshold of a joint compound in a teratology study using information in the dose response curves from the individual agents and the joint compound. Additionally, we develop cost-saving designs for Michaelks-Menten like mod sis used for studying pulmonary clearance of insoluble particles and find optimal designs for estimating biological responses defined by solutions of a differential equation. Innovative theory will be developed to construct these designs and understand their properties, including their sensitivities to model assumptions. [unreadable] [unreadable] To facilitate the use of optimal design ideas in practice, we create a user-friendly website with an array of algorithms for generating all types of designs for linear and nonlinear models, including designs to be developed in this research. The website will require input from the user before a tailored made design can be generated. Practitioners will be able to use the website to evaluate the efficiency of a design under a range of user-selected criteria and search for links to other websites where specialized design software is available. Such a website does not exist now. Our website will educate, inform and encourage practitioners to incorporate more optimal design ideas in their work, thereby saving substantial cost in their studies. [unreadable] [unreadable]